With the development of a modern wireless communication technology, more and more network standards are used extensively. For example, the network standards which are commonly used currently include: a Global Systems for Mobile communications (GSM), a Wideband Code Division Multiple Access (WCDMA), a High Speed Packet Access (HSPA) technology, a Code Division Multiple Access (CDMA) 2000, a Evolution Data Only (EVDO), a Worldwide Interoperability for Microwave Access (WiMAX), the Long Term Evolution (LTE) and the like.
Among the numerous network standards, some have developed interconnection standards which can realize a dual-mode switching between the different network standards, that is, the switching is performed between the different network standards without affecting use of a user; for example, the LTE has developed the interconnection standards with network standards such as the HSPA, the EVDO and the like. However, many network standards, for various reasons, have not developed the interconnection standards, or their interconnection standards are still in an initial development stage and cannot be used commercially, therefore the dual-mode switching between any different network standards cannot be realized; for example, there is no commercially-available interconnection standard between the WiMAX and the EVDO, so the dual-mode switching cannot be performed between the WiMAX and the EVDO.
If there is no interconnection standard, i.e., without a support of a dual-mode switching standard, a terminal working under two network standards will switch very slowly between the two network standards; for example, an existing terminal has been able to work under such the two network standards as the WiMAX and the EVDO respectively; when a terminal needs to roam from an area covered by an EVDO network to an area covered by a WiMAX network, due to the lack of the dual-mode interconnection standard, the terminal has to search the WiMAX network by itself; and the terminal has to search frequency points within a range of a supported frequency band one by one until an appropriate WiMAX network is searched at a certain frequency point, wherein the appropriate WiMAX network means that the terminal receives a signal of the WiMAX network. The search process is relatively aimless, which may consume a lot of time, such that a very long time delay is caused for the terminal to re-access from the EVDO network to the WiMAX network; and, during the search period, the terminal and the network may be disconnected from each other, which lead to very bad user experience.